Expandable interbody fusion device

Abstract

An apparatus and method is provided for interbody fusion including distracting, in a given direction, and supporting opposing vertebral bodies. A plurality of wafers are consecutively inserted between the vertebral bodies to create a column of wafers. The column of wafers is oriented between the vertebral bodies so as to expand in the given direction as the wafers are consecutively added to the column.

What is claimed is: 
     
       1. An expansion member for use in an expandable interbody fusion device for implantation into the intradiscal space between opposing vertebral bodies in a spine, comprising:
 a unitary elongate body including a leading distal end, a trailing proximal end, and opposed lateral edges therebetween defining a maximum width, said body being sized and configured to move within an expandable interbody fusion device and to cause expansion of said device upon such movement, said body having a first beveled surface inclining in a first direction and extending across said maximum width from one lateral edge to the other, said first beveled surface defining a lifting surface, said body including a second beveled surface inclining in said first direction spaced proximally axially from said first beveled surface, said body including a locking surface and a bone filler facilitator selected from the group of facilitators consisting of tunnels, grooves and holes for receipt therein of a bone filler. 
 
     
     
       2. The expansion member of  claim 1 , wherein said body has an upper surface and a lower surface. 
     
     
       3. The expansion member of  claim 2 , wherein said body includes two locking surfaces. 
     
     
       4. The expansion member of  claim 2 , said wherein said locking surface projects from one of said upper surface or said lower surface. 
     
     
       5. The expansion member of  claim 2 , wherein said locking surface comprises an elongate ridge or elongate groove on one of said upper surface or said lower surface. 
     
     
       6. The expansion member of  claim 2 , wherein said second beveled surface extends across said maximum width from one lateral edge to the other. 
     
     
       7. The expansion member of  claim 6 , wherein said first beveled surface and said second beveled surface are substantially planar. 
     
     
       8. The expansion member of  claim 7 , wherein said first beveled surface and said second beveled surface are substantially parallel. 
     
     
       9. The expansion member of  claim 7 , wherein said second beveled surface is adjacent said trailing proximal end. 
     
     
       10. The expansion member of  claim 7 , wherein said bone filler facilitator extends through said body. 
     
     
       11. The expansion member of  claim 2 , wherein said upper surface and said lower surface are substantially parallel. 
     
     
       12. The expansion member of  claim 2 , wherein said leading end is configured as a chevron. 
     
     
       13. The expansion member of  claim 1 , wherein said first beveled surface is disposed adjacent said leading distal end.